Surface treatment of textile materials is to date accomplished when the textile pre-products are in the yarn state or in the completed cloth state or in some cases in the completed product state as is in the case when garments are dyed. Treatment of individual fibers has not to date been an industrially applicable treatment process. A post-treatment of fibers to change the morphology or add qualities to the fibers after growth in the case of cellulose fibers or extrusion as in polymeric or manufactured regenerated cellulose fibers is not an industrial process in the textile industry. Polymeric or manufactured regenerated cellulose fibers are extruded with the desired added qualities in their pre-extruded chemistry state such as in aramide nylon Nomex by DuPont for fire retardancy. Cellulose fibers are treated either in yarn form or in textiles to add the desired qualities such as ammoniated compounds used by Westex in fire retardancy where the textile is treated. Fiber in sliver state is also not used as a vehicle for adding qualities to fibers but rather as a partial step in the yarn manufacturing process. Described herein sliver is composed of fibers in a parallel orientation or ordered fashion and the system described allows for the retention of this ordered fashion while treating the fibers to add desired qualities.
The treatment of the fibers herein will result in either a continuous or a discontinuous coating which herein is denoted as plated for continuous coating and speckled for discontinuous coating.
One of the reasons for the lack of such an industrial process is the fact that when fibers come in contact with a liquid medium, the fibers can bundle into inseparable balls or the fibers can separate and reorient in an unpredictable manner. Further, the problem exists in that, depending upon the nature of the fibers, there may be poor interaction with the solubilized compound in terms of its surface attachment by chemical bond formation or a lack of exposure that will allow for the entire fibers to be treated such as is the case in a cotton ball when only the outer exposed fibers are likely to be treated and then the cotton ball becomes impossible to process.
Often a treatment at a fiber level makes spinning of a yarn difficult due to friction between the chemicals on the fibers and the yarn spinning machinery, as well. As such, treatment at a fiber level does not lend itself to industrial processes in yarn and textile production.
Fabrics which are surface treated can have very different qualities depending on the compounds and compositions used for surface treatment and the desired application for use of the fabrics. For example, textiles treated with inorganic insoluble compounds through an oxidation/reduction process or through sonochemical irradiation or through acoustic cavitation of metal oxides in particular and other inorganic insoluble or poorly insoluble compounds in general are often rough to the touch and have limited use to a consumer because of the feel of the finished product and the dusting of the chemicals that fall off the fabrics.
Even if the amount of chemical compounds that are applied to the fabric is limited to a minimally effective amount or to a nano-size particle, the feel of the fabric often is similar to that of very fine sand paper and therefore unappealing to the touch. Essentially every inorganic compound applied in this manner, such as, silver and silver oxide, copper and copper oxide, zinc and zinc oxide or any inorganic hydrated compound such as sodium borate (decahydrate), alumina trihydrate, magnesium hydroxide, red phosphorous, antimony trioxide, diatomaceous earth, or any other insoluble or poorly soluble compound, will often, when thus applied, provide a rough quality to the textile surface, which renders the textile product undesirable, especially when the textile product comes in contact with the skin.
Further, it is technically challenging to reduce the surface exposure of the surface-applied chemical compounds so that the user will not feel the rough surface when the product is in the form of a yarn or a textile to which such compounds are surface applied. The inorganic nature of most chemical compounds will cause a fractious surface.
Compounds that are attached to the outer surface of a textile are subject to abrasion, which in turn can lead to their dislodging or being scraped away. Since the goal in surface application of such compounds is to achieve reasonable loading at a desired critical level, the same may not be achieved with current methods. Surface application of insoluble particles to a textile or a yarn furthermore provide potentially undesirable color artifacts, or otherwise undesirable appearance and/or feel, resulting in a need to treat such surfaces, to, at least in part, hide the particle. Such masking procedures, however, typically result in loss of efficacy of the masked particles.
Surface treatment with certain classes of desirable compounds, moreover, is typically unsuccessful. The use of poorly water soluble compounds, for example, flame retardant compounds, with existing methods, results in the compounds being readily disassociated from the fabric to which they are applied. Such dissociation provides, in addition to a loss of function on the applied material, for an environmental hazard, as, for example, in surface applied clothing, whereby the compounds dissociate in wash water. Such compounds, for example, brominated flame retardant compounds, which until recently were very common, are now a subject of regulatory scrutiny, as the compounds persist in the environment, bio accumulate in the food chain, etc. (see: Kim Hooper, Jianwen She (2003). “Lessons from the Polybrominated Diphenyl Ethers (PBDEs): Precautionary Principle, Primary Prevention, and the Value of Community-Based Body-Burden Monitoring Using Breast Milk”. Environmental Health Perspectives 111 (1). http://www.ehponline.org/members/2003/5438/5438.html). Clearly, the issue is not related to brominated flame retardant compounds, but rather to any poorly water soluble compound with potential toxicological effect.
For the above reasons the state of the art teaches away from processes for the surface treatment of textiles with poorly water soluble, or insoluble organic or inorganic compounds, and individual fiber treatment, in the current uncontrolled setting, would seem to be an even greater risk factor, given these considerations.
As yet there remains a need for the creation of fiber-based products incorporating poorly water soluble compounds or insoluble compounds, which do not suffer from the limitations described hereinabove. The ability to prepare fiber-based products incorporating poorly water soluble or insoluble compounds, including various natural and synthetic fibers which are non-toxic and provide for such incorporation in a minimally toxic environment while maintaining the activity and protection afforded by incorporating such compounds is as yet unattainable, as well.